Why we need a Downscaling? One of the major hurricane threats is damaging winds. Sustained winds and gusts of hurricanes have proved to be catastrophic for many homes. Most of the damage caused by hurricane winds occurs within the first few hours during a hurricane’s landfall. Hurricane Michael (2018), Harvey (2018), Irma (2017) some of the recent hurricanes cased huge damages across the coastal areas. We need downscaling discussion (not only hurricane but other application as well) to reach out knowledge at meter scale and link its application to the society. With our current and possible future computing powers, we are ready to deliver at 10-100 meters scale applications that will directly connect to the society (LINKS).  

The wind gust generated by large transient eddies are the most likely culprits for producing damage patterns of a few hundred meter in scale or even smaller (Ping Zhu 2008). The coastal hurricane wind damage is determined by various building design codes but at the same time we need to improve our understanding on fine-scale structure of damaging winds.Understanding the wind dynamics of landfalling hurricanes and predicting wind changes at or near the time of landfall are of vital importance, not only for scientific study of land- falling hurricanes, but also for hurricane preparation and assessment of hurricane damage and financial losses in the landfall regions. However, the detailed structure and change of surface winds during landfall, which is controlled by the multi-scale interactions among the storm-scale circulation, meso-vortices, turbulence-scale eddies, and the underlying surface, cannot be obtained from operational numerical simulations (Ping Zhu 2008). 

In our downscaling session, we want people from different background and addressing the challenges in the downscaling techniques for many applications such as landfall cyclone damages in the coastal areas, downscaling flash flood forecasting & reconstruction, applications of using fine scale (at meters resolution) landuse/landcover along with topography, Build Large Eddy Simulation (LES) framework for fine parcel-scale applications (Dynamic downscaling), Statistical downscaling.

The Idea of downscaling session is a good fit to the AMS 2020 Theme as this downscaling session bring greater knowledge of the situation to more positive impact on society (LINKS).

1. Zhu, P., 2008: Simulation and parameterization of the turbulent transport in the hurricane boundary layer by large eddies. J. Geophys. Res., 113, D17104

According to the American Association of Port Authorities (AAPA), “To be able to receive post-Panamax size ships, a port must have a channel depth of 50 feet. By 2030, post-Panamax vessels are projected to make up 62 percent of total container ship capacity. Of the 175 top U.S. seaports only 15 ports have that ability (or currently upgrading to be there)...”

Today's ships are moving through U.S. seaports with little room under their keels. As vessel drafts increase, the navigation margins become smaller and the need for more accurate and timely environmental information increases. Unfortunately, the tools currently available to mariners for making safe operational decisions have not changed significantly over the last twenty years forcing increased vessel load and wait times in ports. Delays and lightering due to the uncertainties posed by environmental factors can equate to millions of dollars a year in lost revenue for shipping companies and ports.

The goal of NOAA’s precision navigation program is to provide high-resolution bathymetry and nautical charts along with real-time observations and forecasts of winds, waves, water levels, and currents for display on navigational display systems onboard ships and also for use by real-time under-keel estimation software. As a result, mariners will be better equipped to make critical navigation decisions. Since precision navigation involves many types and sources of data, it is a coordinated effort across several NOAA offices.